The invention relates to a process for the automated diagnosis of monitored objects, especially of drive strings.
Kinetic effects on drive strings lead to force effects which are transmitted as waves within the machine structure and are detectable as vibrations on the surface of the machine. The detection is thereby carried out by conversion of the mechanical into an electrical signal for example, by way of acceleration sensors and transmission and possibly analogue processing of the analog electrical signal, anti-aliasing-filtering digitalization and digital intermediate storage. The time signal which is present in digital format can again be processed, for example, by frequency band filtering, envelope curve formation or data reduction. By way of a Fourier, in general, a Fast Fourier Transform, one obtains a spectrum, the envelope curve spectrum and the maximum value envelope curve spectrum of the signal. The special lines of the frequencies associated with the kinetic effects embody thereby kinetic effects of the monitored object as well as interference signal portions.
If a spectral line or a combination of spectral lines can then by way of its frequency be definitely associated with a kinetic effect and if one can assume that the amplitude of the spectral line, weighted for the damage type, is not only a component of a wide band simulation but is significant, then the corresponding kinetic effect is present with high probability.
The described method is disclosed, for example, in xe2x80x9cEinflxc3xcsse auf die Zuverlxc3xa4ssigkeit von Schwingungsdiagnoseverfahren an Wxc3xa4lzlagernxe2x80x9d of Rainer Wirth, Dissertation TH Zittau, 1994, and is already used for off-line processes.
The significance analysis stems from the mathematical statistic and is described, for example, in xe2x80x9cWahrscheinlichkeitsrechnung und mathematische Stastikxe2x80x9d, MINxc3x96L Volume 17, B. G. Teubner Verlagsgesellschaft Leipzig, 1988, of Bayer, O.; Hackel, H.: Pieper, V.: Tiedke, J.
On the other hand, there are on-line processes which realize the surveillance of spectra and envelope curve spectra as mentioned, for example, in xe2x80x9cZustandsxc3xcberwachung mit InterMAC in Kraftwerks-, Bergwerks- und Prozexcex2anlagenxe2x80x9d of Schuehle, R., Becker, E., published in Seeliger, A.: xe2x80x9cAKIDA-Aachener Kolloquium fxc3xcr Instandhaltung, Diagnose und Anlagenxc3xcberwachungxe2x80x9dxe2x80x94conference volume of the Kolloquium of May 30 to 31, 1996 in Aachen. Furthermore, the on-line process is realized by way of the amplitude surveillance for individual parameters and also described in the above-mentioned publication.
The surveillance of spectra by way of such on-line processes requires a regular data transfer as well as a regular analysis by the expert. The automated amplitude surveillance of individual parameters is only suited for continuous processes. However, as soon as changes result because of load or environmental effects, the already used processes fail.
It is an object of the invention to provide a process which, by way of the on-line data recording delivers reliable and definitely characterizing features for the remote diagnosis of condition parameters even under load changes and environmental influences and which improves the reliability of the diagnosis and operates cost effectively.
It has thereby been found especially advantageous that a stationary automatically operating data collecting unit on the monitored object monitors the significance of the desired property parameters, whereby the error probability for each damage type is predetermined. If the significance exceeds a selected predetermined value, which means the amplitude of the vibration components associated with the kinetic events exceeds the significance threshold property parameter, the significance controlled data transfer to the monitoring terminal occurs, where the transmitted data are stored and in parallel a report or alarm is initiated.
Instead of the vibration acceleration, the vibration speed or the vibration amplitude can also be monitored as physical property parameter. Apart from the housing vibration, the shaft vibration, the rotation uniformity or the torsion vibration and any other condition parameters can be measured.